Short piece expert distributed round start of class (7)
I believe the answer is:
excerpt
'short piece' is the definition.
'expert distributed round start of class' is the wordplay.
'distributed' indicates anagramming the letters.
'round' means one lot of letters goes inside another.
'start of' suggests taking the first letters.
The initial letter of 'class' is 'c'.
'expert' anagrammed gives 'exerpt'.
'exerpt' enclosing 'c' is 'EXCERPT'.
(Other definitions for excerpt that I've seen before include "Just a few words" , "Short extract" , "Selected passage from larger work" , "Literary section" , "Extract from book or film" .)